STUDY POPULATION AND METHODS Population The study population represented individuals screened for TB over a 6-month period ending in December 2004 as part of a number of community health outreach programs based at the Center of Disease Control in Taichung, Taiwan. Changhwa Veterans Home is a government-expense veterans home with totally 519 residents in 2004. Only individuals with a properly read TST and signed informed consent were included in the study population. If a TST was positive, further evaluation for TB was advised. Anyone found to have active TB infection (12 individuals diagnosed, all from household contacts) was appropriately treated and were also included from the study. No general population low-risk controls were included in the study population. There were no other entry exclusions for the study. Before the TST was administered, a short interview including verbal consent and a BCG scar count evaluation was conducted by an experienced nurse.